The effects of length of overhang on the stress state of a composite beam
With the increasing use of Composite materials in various application - automobiles, aircraft, sailboats, and various sporting goods — the demand for more accurate engineering analysis of composite grows as well. Interlaminar shear stresses in composite beams and plates are produced as a result of free edges, ply drop-offs, three-dimensional stress fields, etc. Characterization of a composite material’s resistance to interlaminar shear is critical to their optimization. A composite beam, consisting of a coupon of unidirectional HERCULES AS4/3501-6 graphite/epoxy material adhesively bonded between steel strips and subjected to four-point bending, can be used to characterize the interlaminar shear strength of the composite materials. Preliminary results indicate the beam’s overhang length affects the failure of the specimen. Three finite-element models were generated to determine the influence of the length of overhang on the stress state of a composite beam. The finite element models are incorporated into an analysis involving plane elements to study the state of stress. Results show that the length of overhang can reduce stresses at the free edge of the beam.